package com.lg.atp.common;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
    
public class FileTypeUtils    
{    
    public final static Map<String, String> FILE_TYPE_MAP = new HashMap<String, String>();    
        
    private FileTypeUtils(){}    
    static{    
        getAllFileType();  //初始化文件类型信息    
    }    
    private static void getAllFileType()    
    {    
        FILE_TYPE_MAP.put("jpg", "FFD8FF"); //JPEG (jpg)    
        FILE_TYPE_MAP.put("png", "89504E47");  //PNG (png)    
        FILE_TYPE_MAP.put("gif", "47494638");  //GIF (gif)    
        FILE_TYPE_MAP.put("tif", "49492A00");  //TIFF (tif)    
        FILE_TYPE_MAP.put("bmp", "424D"); //Windows Bitmap (bmp)    
        FILE_TYPE_MAP.put("dwg", "41433130"); //CAD (dwg)    
        FILE_TYPE_MAP.put("html", "68746D6C3E");  //HTML (html)    
        FILE_TYPE_MAP.put("rtf", "7B5C727466");  //Rich Text Format (rtf)    
        FILE_TYPE_MAP.put("xml", "3C3F786D6C");    
        FILE_TYPE_MAP.put("zip", "504B0304");    
        FILE_TYPE_MAP.put("rar", "52617221");    
        FILE_TYPE_MAP.put("psd", "38425053");  //Photoshop (psd)    
        FILE_TYPE_MAP.put("dbx", "CFAD12FEC5FD746F");  //Outlook Express (dbx)    
        FILE_TYPE_MAP.put("pst", "2142444E");  //Outlook (pst)    
        FILE_TYPE_MAP.put("xls", "D0CF11E0");  //MS Word    
        FILE_TYPE_MAP.put("doc", "D0CF11E0");  //MS Excel 注意：word 和 excel的文件头一样    
        FILE_TYPE_MAP.put("mdb", "5374616E64617264204A");  //MS Access (mdb)    
        FILE_TYPE_MAP.put("wpd", "FF575043"); //WordPerfect (wpd)     
        FILE_TYPE_MAP.put("eps", "252150532D41646F6265");    
        FILE_TYPE_MAP.put("ps", "252150532D41646F6265");    
        FILE_TYPE_MAP.put("pdf", "255044462D312E");  //Adobe Acrobat (pdf)    
        FILE_TYPE_MAP.put("qdf", "AC9EBD8F");  //Quicken (qdf)    
        FILE_TYPE_MAP.put("pwl", "E3828596");  //Windows Password (pwl)    
        FILE_TYPE_MAP.put("wav", "57415645");  //Wave (wav)    
        FILE_TYPE_MAP.put("avi", "41564920");    
        FILE_TYPE_MAP.put("ram", "2E7261FD");  //Real Audio (ram)    
        FILE_TYPE_MAP.put("rm", "2E524D46");  //Real Media (rm)    
        FILE_TYPE_MAP.put("mpg", "000001BA");  //    
        FILE_TYPE_MAP.put("mov", "6D6F6F76");  //Quicktime (mov)    
        FILE_TYPE_MAP.put("asf", "3026B2758E66CF11"); //Windows Media (asf)    
        FILE_TYPE_MAP.put("mid", "4D546864");  //MIDI (mid)    
    }    
    
    
    
    public final static String getFileByFile(InputStream is) throws IOException {    
        String filetype = null;    
        byte[] b = new byte[10];    
        is.read(b);    
        filetype = getFileTypeByStream(b);    
        return filetype;    
    }    
        
    
    public final static String getFileTypeByStream(byte[] b)    
    {    
        String filetypeHex = String.valueOf(getFileHexString(b));    
        Iterator<Entry<String, String>> entryiterator = FILE_TYPE_MAP.entrySet().iterator();    
        while (entryiterator.hasNext()) {    
            Entry<String,String> entry =  entryiterator.next();    
            String fileTypeHexValue = entry.getValue();    
            if (filetypeHex.toUpperCase().startsWith(fileTypeHexValue)) {    
                return entry.getKey();    
            }    
        }    
        return null;    
    }    
        
      
    public final static String getFileHexString(byte[] b)    
    {    
        StringBuilder stringBuilder = new StringBuilder();    
        if (b == null || b.length <= 0)    
        {    
            return null;    
        }    
        for (int i = 0; i < b.length; i++)    
        {    
            int v = b[i] & 0xFF;    
            String hv = Integer.toHexString(v);    
            if (hv.length() < 2)    
            {    
                stringBuilder.append(0);    
            }    
            stringBuilder.append(hv);    
        }    
        return stringBuilder.toString();    
    }    
}  